This invention relates to the art of probing into a vessel containing a high-temperature fluid material, as for sampling, and/or measuring the temperature of, the fluid material. The invention has particular utility in conjunction with steel converters and other refining furnaces including degassing furnaces, electric furnaces, and mixers, as well as ladles for use with such furnaces. In these applications, therefore, the invention pertains to the art of probing the molten metal bath for the noted purposes.
Steelmakers have usually resorted to the use of a secondary lance (sublance), in addition to the primary oxygen lance, in probing into a converter for the temperature measurement, and/or sampling, of the bath. The use of the sublance gives rise to serveral inconveniences and difficulties. First of all, since the sublance is inserted into the converter from above and is of considerable length, it requires a large space over the converter.
Another difficulty is encountered when, as has frequently been the case, the iron or slag within the converter adheres excessively to the sublance. Such iron or slag adhesion to the sublance may even make it impossible to withdraw the sublance from the converter through its mouth hood, thus demanding a rest in the converter operation. The stripping the iron or slag from the sublance is also a difficult and time-consuming job.
A further inconvenience arises from the fact that the sublance must be inserted into the converter in a position offset from the converter axis, so as not to interfere with the oxygen lance extending along the converter axis. Thus the sublance receives greater heat from the center side of the converter than from its wall side. Inevitably undergoing thermal deformation, therefore, the sublance is usually bent toward the center of the converter.